Control system for a variable motor vehicle transmission



April 30, 1957 H. J. M. FORsTER CONTROL SYSTEM FOR A VARIABLE MOTOR VEHICLE TRANSMISSION 3 Sheets- Sheet 1 Filed Dec. 16, 1952 H L W G m W k I Il 4! l: l I I l I l I II. W 0, H nu; 3

Speed of 7'raz/e/ u w 7 m w W A 4 q g 9 nb w mum r m m w 55 V 3 E m k m M m April 30, 1957 H. J. M. FORSTER CONTROL. SYSTEM FOR A VARIABLE MOTOR VEHICLE TRANSMISSION 3 Sheets-Sheet 2 Filed Dec. 16, 1952 IN VE N TOR HANS JOACH/M M. Fo'ksn-R ATT RNEYS April 0, 1957 H. J. M. FORSTER 2,790,328

CONTROL SYSTEM FOR A VARIABLE MOTOR VEHICLE TRANSMISSION Filed Dec. 16, 1952 '5 Sheets-Shet 3 4 Warma/ l p '2 Jpevd 0% Travel Juvemar #40: a c 6/0: Al Harrier 82044 -4 flza/w ey;

United States Patent ,.CONTROL SYSTEM FGR A vARIAnLaMoroR VEHICLE TRANSMISSION Hans Joachim'M. FiirstenrStuttgart-Bad CannstatQ-Gep many, assignor, to Daimler-Benz Aktiengesellschait, Stuttgart-Unterturkheirn, Germany Application December 16, 1952, Serial No. 32 6 ,2 Claims priority, application GerrnanyDccember 1951 37 Claims. "'(Cl. 74-472) My invention relates to a control systemfor a va riable' motor vehicle transmission and, morerparticularlm to ar system -forscontrolling a transmissioniot the,typei adapted to be set to any one of a plurality of ratios of -tran s mission.

It is the primaryrobjectof rny .hivention ,;to. prgvide a control system which will automatically control the,

transmission in a manner conforming to the best possible extent to all requirements arising under different; conditions'of operation. More especially it is anpbject of the present invention to provide a control system -for the purposedindicated which. will automatically shift the transmission from a certain ratio to the next higher ,speed ratio whenthe driver operates ,his vehiclewithin a arede etmin d vrangei p and s-dai a qgd presses the accelerator, saidcontrol systemnbjeing opera 'tive, however, when the speed, of ,the vehicle exceeds apredeterrnined limit to eiiectsuch shiftindependentlyq of the position of theacceleratorr It isanother obiectof I the presentinvention to provide a control systernwhich Fig. 10 showing the position of theyalve for set t mg 2,790,328 B e ted Ann .9

dice

; Figs; '7;,;8- and 9 are graphs indicating thefiuid pressure in dependence on the vehicle speed, such fluid pressure lke the system to idling,

Fig. 11-. showing the positionviof the valve tor setting .sL th System to t braking- 1,.and

5- Fig 12,-Tshowin g the1position ofvthexvalve for setting Figi 'll showing the position of ,the: valve for setting 1 'the'system to s ynehronizef f I I I a I s h In ,Ei gs 1, 2 and, 3 graphs are ,shownin which the 20,.POWeiioutput N is indicated in, dependence, on the speed V, of the vehicle, Fig; 1 applying to ,the setting of the transmission to thefirst, second, thirdand speed, Fig. 2, a'pplying to the setting ofuthe transmission; to the first, Second and third speed, and Fig. 3' applying to the I setting of the transmission to the first 1 and second speed,

it being understood that,thelmaximurri sewer; output at a pertain speed depends on the effectiveratio of transmission Nl indicates the maximum power outp'ut with the transmissionsetto the first speed ;ratio; NZjin d icates the maximumpower output with the t tranSmis siOn Qset to the second speed ratio; N3 indicates the maximum power .output of thetransmi ssion being set to thethird speed ratio, and N4 indicating the maximum power out- Fig 9 applying when the system I is set to fbraking II,-

put'of the transmission being setto the fourth speed will automatically shift the transmission from a higher ra ti0..

,yehicle drops below a certain limit.

speed ratio to thenextdowerspeed ratio irrespective of I I V I I II II I the position of the accelerator .whenevertthe speed ofgthe gdqscu zedhereul f rm y b? .stofltre e dfiemntcpnditions,.to-wit Further objects of the present -invention will appear )1 qjfno m iiwhich edun er normal d I Y from the description of a specific .embojment, ;thereof 93Q 9m Accor ding to, the inventionthe control, system: to be illustrated in the accompanyingdrawings, itheing uriderstood that such detailed description serves the purpose of illustrationrather than. that oflimitation o ithe ipyem (S To fbraking I whichrnaybe used in. citystrafiic and while coasting downhill where it is desired that the engine exert a certain braking eifect on the.vehicle, andengine in dependence on the speed for difieren in dependence onthe-yehiclespeed for tw I I ratios. of transmission, thelatter. being Sel I PtO; v 11,! v Nd the various elements of my novel fluidsc niro system for a motor vehicle transmission showingt thenvarious tion.

\ .In the drawings:

' (3) ITo hr aking .II which is, used under,similar b jmorcextrerne conditions than the preyiou setting.'

jlFig."l is a graphindicatingthmpower outputs f th Whenithe transmission has peedsetjro iio narmhe -t iovel controlIsystem functions in such :afm'anner that the transmission may II he lautomatkally shifted. from one ratio of transmission'to the other ratio'of transmis- 0 sion wheneverthe speed of the vehicle bordersuthe' noise transmission with the control system set V t'olignorma'l Fig. 2 is a similar graph indicting the pow of the engine independence on-thesp'eedio ratios of .transmissionwith the,,contro l-,,syste ,the operation referred to hereinafter as ibralsinglf limit'above whichthemotor noise is louderlthanfthe Fig. 3 is a similargraph indicating ,the power "noiseproducedby the. wheels of the vehic1e,and,, the,b0dy thereof and, therefore, gives the ajs a1 ers,sniinm- --fortable sensation as though the engine were racing at I an excessive number of revolutions;

-When the vehicle travels. with the transmission set to Fig. 4 is a. diagram indicatin the war-ions ossible a t g e p the first speed ratio under full power, thespeed V of the positions of the gear shift lever movable ,wi thin t\ /p ;.different paths,

Fig 5 is IaI diagrammatic segtion'ql i g mz 0f the transmission willincreasefrom the point 0 up to --.t-hepower output amounting to' A, the control system to elementstof such control system andsdiagrammatically indicating the conduits-connecting. thesama'stheaparts 'to normal, the transmission being shifted tp thegsecond speed ratio, l-iig. 6 is a cross section takeu-throughthe pressurerstep controller, an axial --sec tion; ofwhich is included in Eig.

not fully open thethrottle, butopens the samefpartially i. only thus I causing the powe r output to in'crease from 0 -r to 'A', BS- l-IldiCRid by the dotted lineNlf the Fig. 5,

limit G0 or is below said limit, thelatter, constituting a a vehicle will increase from 0; to V1 and .thepower output --the-point A As soonfas the speed VI has been attained, I

be describedrhereinafter functions to automatically. shift the transmission tothe second speedJ-atioresulting in ahowever, in accelerating the vehicle from 0, to. V1 does I elsystemiwilt be'operative to peiforrnitheshift ng o "'n' f ngealme fies-6rd wat the point A. With an even smaller power outputiof the engine, for instance as indicated by the curve N1",

the novel control system will shift the transmission from the first speed ratio to the second speed ratio as soon as the power output curve intersects at B, the full power curve N2 representing the power output of the transmission shifted to the second speed ratio. Whenever in the diagram of Fig. 1 the power output and the speed are defined by a point moving through the curve N2, the shifting operation takes place. Therefore, this curve will'be referred to hereinafter as the shifting-up curve.- If the driver would maintain the accelerator in its position, the

, power output would drop upon the shifting operation to a correspondingly low point located within the area of the second speed ratio, e. g. to B. Since the driver, however, will instinctively fully depress the acceleratoriupon the'gear shifting operation, a drop of power is practically avoided. The first speed ratio area, i. e. the area including all of the points indicating the vehicle speed and the power --output attainable with-the transmission being set to its first speed ratio, is. defined by the'points.0' A -B,'t-he put curve intersects the line 'ti B'-A.

Similarly, the transmissionis'shifted from the second :speed ratio tothe thirdjspeed ratio whenever the curve representing the poweroutput in dependence on the vehicle speed intersects the line CD-E'F which is offset twice. Whenever thevehicle is operated at'a speed and ate. power represented in Fig. 1 by a point located to the left of this line C'DEF, the novel control system will set the transmission to the second speed ratio. Whenever the power output and/or speed of'the vehicle is so altered as to be represented by a point in Fig. 1 moving to the right of the line C-DE-F, the transmission will be shifted to the third speed ratio. The point F is located on the full power graph N2 of the second speed ratio, the same being the curve indicating the power output with the throttle being fully open, to wit the highest attainable power output in second speed. .Here again point F is located on or below the noise limit G0. Similar considerations apply to the gear shifting operation shifting the transmission from third to fourth speed. Therefore, such gear shifting operation occurs shifting operation taking place whenever the'power outwhenever the power output and/or the vehicle speed change in such a manner that the point representing the same would pass through the line GHI-'K.

As will appear from Fig. l, the boundaries ofthe different ratio areas in thegra'ph are preferably so correlated that the maximum speed VI of the first ratio area coincides with the minimum speed V1 ofithe third ratioarea. Similarly, the. maximum speed V2 of the secaveasas ond ratio area'GF-E-D-C coincides with. the mini- $11111 speedVZ of the fourth ratio area G-HI1- I- Asfla result, there are at least two different'ratios of transmission available, a higher ratio and a lower ratio, for the operation of the vehicle at any particular speed between zero and V3. Thus, when the vehicle is driven at a speed higher than V1 and lower than Y2 the transmission will be set by the novel control system to the sec- 0nd ratio if the point indicating the power output is located within the area DBFE, or -will be set to the third speed ratio if the point indicating thegpower output is located within the area C-D-EG. .Since the shiftingup.linegi e. the boundary between two adjacent ratio areas, coincides with the full power graph N2; N3 or N4 of the next higher ratio, the novel control system includes as an element means responsive to the vacuum produced in the intake manifold of the engine,.

- such vacuun being substantially.proportional to the drivmgtorque exerted by thejengine upon the transmission. Thps, the shifting-up line constitutes a line of constant intake vacuum which below the noise 'limituGt) corresponds substantially tothe torque characteristic of the 4 1 engine. .Therefore, the intake vacuum is one. of the controlling factors of the novel system. It may be used, for instance, for controlling the fluid pressure employed to engage clutches in the transmission. Preferably, the different ratios of transmission constitute a geometrical progression. In that event, the critical intake vacuum resulting in the gear shifting operation will be the same for all ratio areas.

Once the transmission has been shifted from one ratio to the next higher speed ratio, it will not be shifted back unless the speed drops below the lower limit of the as sociated speed-power area, such lower limit being preferably slightly displaced with respect to the lower limit that was previously effective during the operation of shifting the transmission from the lower ratio to the next higher ratio whereby a hysteresis effect. will be attained which prevents the transmission from being continually shifted to and fro when the vehicle is operated at a speed close to the speed limit. This will now be explained with reference to an example. Let us assume that the transmission has been shifted from the second speed ratio to the third speed ratio, the speed exceeding V2. Then, when the speed drops, the transmission will not'be shifted back to the second speed ratiounless the speed decreases below V2 which is slightly less than V2.

Should the driver operating the vehicle within a certain range of speed wish, however, that the transmission be shifted to the next lower speed ratio, he may do so by a suitable manipulation of the control system, for instance by the so-called kick-down, i. e. by depressing the accelerator pedal or other power control member beyond the full load position.

Since in normal service the period of operation of the transmission in the first speed ratio is but very short, and since preferably a free-wheeling clutch is operative to transmit the lowest speed, and since the initial acceleration of the vehicle attainable with the second speed ratio of the transmission is fully sufficient, a lower limit speed for the second ratio area is preferably dispensed with such area reaching down to the point 0 whereby the second speed area is extended to CDE-FB-'- "Nevertheless, the driver operating the vehicle at a power and a speed represented by a point located within the area V1D-EFB-t) is able at any time to shift the transmission to the first speed ratio by the kickdown manipulation of the accelerator pedal. The same applies to the operation of the vehicle at all other ratios of transmission. Thus, the'driver may start the vehicle in the second speed ratio unless he has -shifted the transmission to first speed by the kick-down'of the accelerator. .In this manner, the following advantages are secured:

"transfer a definite, even though limited, torque producing a tendency 'of the vehicle to creep. That tendency is considerably reduced when the transmission is'setto the second speed ratio while the-engine is idling and the vehicle is at a stop. Moreover, under normal conditions the operations required for shifting from first to second speed or from second to first speed are saved. The e1imination of, such operations is highly desirable, particui larly inasmuch as they are very likely to produce shocks owing 'to:the considerable jump in driving power.

Fig. 2 illustrates the conditions of operation of'the vehicle ensured by the novel control system when the same has been set to the braking I condition. In this 'condition of the system the transmission will not be auto- -matically set to the fourth speed ratio, no matter how fast the .vehicle maybe driven. lffthe vehicle was previously' driven with the transmission set to the. fourth T speed-"ratio, the setting of the control system to braking I which may be elfected by the driver in view of trafiic or road requirements will immediately cause the transmission to be shifted back to the thirdratio. Since for any speed 5 -of the vehicle two ratios of transmissiononly are avail- I iWhen the vehicle is idling the hydrodynamic clutch will able; iris unavoidable-that with the setting iof 'ratioandwicewersa is controlled irithefsame manner as ---desc1ibed abovewith'reference to the normal condition of thecontrol system. Therefore, the first gear ratio will be available for the speeds and power outputs. included 1 in "the" area A+B.

;Fig." 3"illustrates the operating conditions of thetcontrol -system' whenathe same has beeniset to bralgirigiII; 'iIn'" -this-ev ent the control systemjwillset the/transmission either tothefirst speed ratio or to the second speed ratio, -but-not. to the third .or the fourth; speed jratio. Therefore,- in this condition the 'controlsystem permits F'safe operation of the vehicle ico'asting on steepdowm grades, the engine acting .as a brake -limiting the,spee d of the vehicle. "With this setting of the control system both the first speed ratio and the second; speed ratio maybe used up to the *full'power. output'of .the engineiindicated "by-'the'curves 'N1 and "N2; The automatic shifting-up :-boundary for the first speedratio condition isjextended up to avehiclespeed of V1x'which'preferablyjcorresponds to V2; :The'shifting-down boundary-.in'thisjcase is'lo- "*cated at a lowerispee'd V2x"., whenthemon'trolys'ystem :conditioned for braking I is' seL'by' thefdri ver. to "brakingII, such setting operation preferably performed bymeans of'the customary control lever.,moimted on the steering column causes the transmission to'be-automatically shifted to thesecond. speed ratio shouldit have been set to the third ratio'before; The condition" braki ng 'II.-has been found to be particularlyuseful under driving conditions requiring a maximum of acceleration bfnthe vehicle in the first gear condition or am'aximum ofen gine 'braking in .the'second gear condition. L 'As'willappear fror'n the foregoing explanation ofthe "tunction'of the novel control system,-theessential-features of the present invention are the following: .The'operation of shifting the transmission fromgone speed ratio tothe next higherspeed ratiois automatically eiiectedbetween a lower-speedlimit and anyuppergspeed limit in dependence on the torque .oftheeng'ine, thet'ran smission being soshifted at any rate, i. el irre spectivefof thetorqueof the engine, whenjthe vehicle speedexceeds the-upper limit. Preferably, theshifting-up operation: is .automatically effected in dependence] on,. the driying torque; whereas the shifting-down operation. isuetfe cted "either automatically as a result .of a.lre'duct'ion .of .the vehicle speedbelow a certain lower limit, .or -as a result of a. manipulation by, the driver performed :vsihile. the vehicle is travelling within the speed limits .ofthe range of'speed coordinated to the particular ratio then effective. More particularly, such manipulation consists in kicking down the accelerator pedal beyond its full power position. The novel control system may be conditioned'for three different functions, to wit for ,normal,. for. .bral ing.I,

and for braking 11.. In normal thecontroli's ysitem may shift the transmission to any one of the available.

ratios, for instance to any one offour speed ratios. In braking I thecontrol system .may'shift theftrans mis sion to any one of alower number of ratios,;'e. g., tojany jone "of three-speed ratios. Inb raking I11 thecontrQLsysftem --mayset the transmission to'any one of a still smaller number'-of=ratios,- e. g., two spe'edfratios. Preferably, thetcontrol systemywhen conditioned by-the' fdriver for iiaatriorezlimited function, is-operative-to increase thespeed miss-ion"'-is shifted to ahigher speedmatio.

-The present inventionis' agyaluable contribution tgjthe art involvingthe following-advantages: y 5 (1') Thesshifting-up boundary, such as" or G-"HP-K, may be so chosen that thegtransm ssion will be-shifted to the next higher-"speed ratiowheneyer the same permitsthe samepower output to be-perfgrrp'ed with a reducedfuel consumption (with-the same or with 10 another throttle adjustment of the -engine) ".Where "the engine is of the (Into-type in which 'agfue'l' mixture is ppm- ---pressed --and- -ignited,-* the shifting-up' boundarygsu'ch' .as C{ D'-E"F- or 5 substantially 1 coiizgergzles withthe full power characteristicgof the following ispeed ratio. 7 v

In engines of the Otto type, the full.,powercha'racteristicofthe-nextsp'eedra'tio' is substantially "identical with --a characteristic denoting constant intake vacuumjorthe ratiof-oftransmissionefiective' atfthe time. lnjdiesel. enginesirr -which'the-fuel is injected into .a compressed air charge-the full powencharacteristic"of .the inextj'ratio 1 substantiallycoincides with a characteristic denoting 'jcon- -stant fuel control adjustment. Therefore; the intake vacuum;- -or the-position of the fuel-control membegof '25 -the-diesel-fuelinjection pump may be used as determining theshifting-upboundary. "With an 'en'ginejof the Otto-typeforinstance, thecharacteristic indicatingcom stant-intake vacu-urn-,--when used as a controlling factor, has-the result that-the shifting-up operation takes place at a -vehicle' speed which is the higher the. widerjthe throttle willbe opened. Therefore, the ratioareas, such as- -0 'F-E'-D+G' and" C-D'E'K-I+Hi' in 1 Fig. 1 canb'e determined solely by determining the speed limits at which the shifting operations" shalltalge plaice.

(2) The automatic shifting-downoperation ca'njlikewise take place independence on the intake vacuuntof {the engine. Itappears preferable, however, to restrict the 'ilimit 'for the-:shifting,=upoperation, at theltpansv conditions resulting in" the shifting-down,operation'to' a reduction of thevehicle speed'below a lower. limitiwhich is .preferably'so chosen that below said limitalower fuel consumption is attainable with the lower speed ratio. ---Said lower limitof-the speed coordinated to the shiftingdown operation shall be chosen at any rate below'the shifting-up limit in order to avoid'undesirable oscillations of the-control system.

"While the-control system keepsthe transmission set to the second, third, fourth, ora higher speed ratio, it is conditioned at any time to be rendered operative by. a

to the next lower speedratio. In such event, it isijthe control system and notg-the driver that determines in dependence on the speed of the vehicle which speedratio is to be set up. With such function of .the control system -the fuelconsumptionmay be reduced to a minimum,.because a full opening ofthe throttle will not alwaysirnmediately result in the full power output of the engine which otherwise would only too often be usedinadvertently.

sponding shifting-up speed limitin order to L desirable oscillations'of the control system.

6 -(3)@The speed limitsindicated in Fig. 1 representing (4) The chance available to the driver of coirditioniiig.

'manipulation of-the driver, such as the kicking down of the accelerator pedal, to shift, the transmission back The speedlimits of thecondition of the. controL'systern for the performance offthe shifting-down operation are preferably located somewhat below the corre-. prevent un- V thefunetion ofthe control system when conditioned for the engine.

. power output and the possible braking effects so as to suit road and trafiic conditions. By so conditioning the control system the driver may use a low speed ratio up to the full power output of the engine since the trans mission will no longer be shifted automatically to a higher speed ratio. Hence, the low speed ratios, for instancethree speed ratios, maybe utilized to produce a braking effect by the engine ondowngrade travel. Thus,

7 the vehicle may be driven with the first speed ratio or the second speed ratio up to the maximum number of R. P. M. of theengine which is sometimes desirable to overcome extreme upgrades of the road or to attain a maximum acceleration or a maximum braking effect of Preferably, the speed limits for the shifting operation are so chosen that at any speed of the travel of the vehicle (under certain circumstances except for the v highest range of speeds) two ratios of transmission are ..-available, the control system being: operative toautomatically shift the transmission to the higher one of the two ratios, whereas the restoration ,of the transmission of the lower ratio preferably depends on the kick-down of the accelerator pedal by the driver beyond the full power position of the pedal. Under normal conditions the higher 7 one of the two ratios is effective resulting in a low fuel consumption. Where the traflic conditions or road conditions require a frequent use of the second speed ratio, the driver may condition the control system to braking I thereby increasing the power area available for small speeds. For limiting the automatic function, such as the automatic shifting-down, to the second speed ratio for the purpose of braking the vehicle, the driver may condition the control system to braking II. Whenever the control system has been conditioned for braking I or braking II the engine may race at full speed which offers advantages in cases of emergency, for instance in event of a failure of the brakes. The control system may be so devised, however, that even if set to braking I or braking II the transmission will be shifted to the next higher speed ratio in event of excessive R. P. M. of

the engine. A V

' Prior control systems for motor vehicle transmissions adapted to be set to any one of four difierent ratios could be set to a normal condition and to a braking condition in which the transmission was set to the second speed ratio. Since, however, most of the downgrades have an inclination; of less than ten per cent. the third speedratio is sufficient as a braking. speed ratio. The limition to the second speed ratio as a braking ratio reduces considerably the usefulness ofthe automatic control system, because either the friction brakes of the wheels must be used orthe driver must alternatively set the control system to normal and to braking or he must give gas with the transmission shifted to second. Contrary to such prior art the present invention affords a much better utilization of the various ratiosof transmission and conforms much better to the road and trafiic conditions without in any way encumbering the operation of the. vehicle and without increasingthe cost of manufacture. .Moreover, the invention relates to a pressure step controller, preferably in the form of a centrifugal governor controlling various super-pressure. valves or a .superpressure valve having a plurality of dischargecross sections. Finally, the invention relates to the combination with'such a pressure step controll'erin connection with r a conditioningxvalve which'conditi'ons the control system to normal, braking I-"or-br'aking ll a'nd is operative adapted toseal discharge openings for the discharge :of

conduits which are rendered elfective successively.

Preferably, a manual setting lever adapted to condition the control system to normal, braking I or braking II is so mounted on the steering column of the vehicle as to be capable of being rocked within an upper plane or within a lower plane. In one of the two planesthe lever may assume three positions, one for reverse, another for idling, and a third one for parking. Further features of the present invention involve the use; of pilot valves and gear shift valves in connection with the conditioning valve and a pressure controller. The control systemis operated by fluid which is under pressure except in the idling condition, and by fluid pressure available even in the idling condition, both fluid pressures being-derived from the same source and being subject to the same control by the pressure controller. v V V A primary pump geared to the engine and a secondary pump geared to the outgoing shaft of the transmission may be used. In this event, a valve maybe provided for the primarypump, said valve being controlled by the pressure controller, preferably through the intermediary of a duct leading to the lubricating points and to the hydrodynamic clutch, said valve disconnecting the primary pump as soon as the ducts leading to the clutch-actuating rams have been opened by the pressure controller and particularly when the secondary pump becomes operative. The valve may serve at the same time as the superpressure valve for the lubricating pressure.

In Figs. 4 to 13 the novel control system having the function described with reference to Figs. 1, 2 and 3 is shown more or less diagrammatically, it being understood that the control system is applicable to a transmission of the type disclosed in my earlier patent application Serial No."245,l3'l filed on September 5, 1951, now Patent No. 2,756,616, dated July 31, 1956, said transmissionincluding a valve housing mounted on the transmission casing and adapted to accommodate the various valves illustrated outgoing shaft of the transmission and theslowly. revolving first gear. Since at any time 'such first gear can be overtaken by the outgoingshaft when the latter is driven through any one of the other gearclutches H, III, IV, the

toothed clutch operable by ram I may bekept in engaged condition as long as the vehicle istravelling forward at any speed. Some of the elements to be described hereinafter form the subject matter of my co-pending application Serial No. 320,032 filed on November 12, 1952,

which corresponds to and claims the invention priority of a German patent application filed Daimler-Benz Aktiengesellschaft, a joint stock company organized under the laws of Germany, on November 16, 1951. For the pur- GO poses of the present disclosure reference may be had to such 'co-pendingapplication, and the. disclosure thereof is to be considered part of the present disclosure.

In Fig. 4 I have diagrammatically illustrated the various possible positions to whichthe hand levermay be set for conditioning the control system, a slotted guiding member being employed to guide such hand lever, said guiding -member having twoguideways 10and 11 connected by a transverse guideway 12. The guideway 10 determines when so set to selectively connect the gear shifting means to. a source of pressure fluid or to disconnect the same therefrom.'- Preferably, the pressure, step-controller is constituted by a centrifugal governorlincluding 'a plurality of flyweights acting'atfthe same .timefas valve bodies:

the setting positions for conditioning the system to idling, normal, braking I, and braking II, whereas the secondguideway determines the positions of the hand lever'for conditioning'the control system to freverse and parking. Preferably, means are provided to tempo- Irarily brakef and stop the driven member of the hydrodynamic clutch whenever the; lever passes transitional For sake of simplicity the valve:Rh: disclosed in. my: last 1 mentioned -co-p,en,ding prior. application. has been I omitted .-in ;Fig. 6. It is-to be understood;however, that such'valve .a-Rlt which'serves thepurposeof producing the temporary -.bralging:eifectrjustreferred to .andsalso serves 'to de-energiZeZ altoftherams including ram I is, in1fact,-:included in the; control :system though not specifically: referred. to .hereinafter.

. A resilientstop- 13, is preferably provided in the guideway 10. Therefore, the driver when; shifting the setting -lever farther than the hidlingi position must overcome the ,IQSfliGIltldSiStEtIiCE offered by the stop 13 before the shiftj ing lever; may be moved. through guideway; 12 into. the

guideway 11. In this way, an inadvertent-.setting iof -the-lever from-.idlingi to-reverse, or: .fparki'ng is obviated.

, In;Figs. 5;-10, 11; 12--and'13 .a lever v16is1shown which 1 is operable by-ihehand-levei: heretofore referred to and 7 "may be moved by the same to;any :one-ofthe; five positions .idling,- .normal, braking I," braking II,.,a nd .,-synchroni ze,-.; the five positions-beingshown in,Fig. '5.

. The.conditioning-.slidetvalve Q includes anupper section Qladapted to control the pressure step controller R and a .lowerportion QZ- adapted to; control aiplurality ofpilot valves and geareshi-fting valves. A. source of operating .fiuid is constituted by- -a pump Rwhich feeds improper- ,-...tion to the speed of. the..-vehicle and is ;preferably.;geared to.,the universal shaft of thewehicle' or tothe outgoing- .shaft .of the ..transmission: .Frorn P- the fluid is fed throughconduit 14and a branch-conduit 15 to a superpressure valve U, and is fed through abranch conduit .71

in a manner to be described later to the-.- conditioning section. Q2 of the.va1ve Q .and thence to therpilot valves.

The super-pressure valve U comprises avalve'rnember 17 slidablyguided in a cylindrical bore ofthevalve casing and urgeddownwardly by a spring lfi -towards its lower end position... The valve controls a plurality ofdischarge ports, such as ports 20, Hand 22. ThGfIOWCI- end ofthe valve member 17 is hollow. andhas holesconstituting a permanent communication between conduit15 and a port 19. The ports-19 and 20 .open into a cylindrical; bore .7 23 accommodating the upper section Q1 of -the condition ing valve, whereas-port 21 is connected'by a duct ;24 ;to

one of the four chambers of the pressuregstep .controller R; .The port 22 finally is put on. exhaust communicating with a return linenot shown. 7 .ThesectionQl of theconditioningvalveincludesthre piston members. 25, 26 and-27 connected bynthewalye stem in spaced relationship, the spaces between the. piston members being denoted at-=28..and -29. Thegcylindrical bore 23 is provided with peripheral grooves communicat- ',ing with, conduitsfiii, 31 and 32 leading toacylindrical bore 33 accommodating the shaft 34 of the-pressure step controller R. The shaft 34 is preferably geared toqthe --o,utgoing, shaft of the transmission to bedriven at a speedproportional to that ofthe travelo f theayehicle. The. shaft 34 is provided with founperipheralzgrooves [35, 36, Hand 38' individually.connectedwith chambers 43,44, 45 and 46 .by. longitudinal-ducts 39,. 40,'41 4' 1nd 42 provided. within .the .shaft .34, as. v.will appeanwfrom Figs. 5 and 6. The chambers 43; 44, 45, 46 areprovided within a head integral with.,shaft -34--being distributed about the axis of rotation of: the head and.be ingindividfually connected, byaradial bores with the longitudinal ducts 39, 40,41 and-42, asshown in:Fig. 6;. Balls 4 7, 48,;49 and 5t are .accommodatedwithin.thechambers, the latterbeing closed by peripheraltlidshaving a threaded engagement with thehead, theuouter face ofwzsnch lids 10' 'vehicle is in motion the headed shaft'34-constitutingthe pressure step controller revolves subjecting theballs 47,48, 49and 50-to a centrifugal' force tendingto press the balls upon the+lids thereby closing theoutlets .:51, 52, 53, 54$ The leaf-springs-SG, 57, -'58= and 59 are -15 *biased, the bias being so differ'entiated that-as the rotary a speed increases; first ball- 47 and thereaftersuccessively balls 48, d9-and 5fi wille-close the associatedoutlet. If desired, such outlets'may have diiferen't diameters.

When the-vehicle is atn'est or is travelling at a low enters the bo ttoniof valve member 17 and thence through the-holes provided therein flows through port 19, space 28,- port' 30,-peripheral-groove 35, and longitudinal duct -39 communicating therewith to the chamber 43 of the controlle'r' R. i1 Since the outlet 51 of this chamber is '-opeii,-the-fluid may freely escape. Thus, a comparatively ----low pressure'only will be maintained inlpipe' 14. -As the speed increases beyond a certain limit, however, the centrifugal; force acting on ball 47 will overcome the "bias-ofrspring- 56 and'will-close opening 51. As a '=-r esult,-the pressure 'acting onthe bottom of valve'rnem- -"-ber"=17-.'will lift-the same contrary to the tendency of spring' i8wThe-pressure of valve member 17 exerted upon the fluid increasesthe pressure of the same'ac cord- SS in-gly'. This'pressure' will-have reached a certain limit whenthe valve-17 uncoversthe port 20 constituted by a pe'ripherah groove in the 'cylindrical bore of the valve rming. Through-this'po-rt the pressure oilescapes-via space 29,=port=-31-, peripheral groove 36 of shaft-34,

'40 longitudinal-- conduit 40,:the-chamber' 44, and the'outlet 52. Upon a further increase of therate of travel of-thevehicle; ball 48..will be caused by-the-increased ..=.centrifugal force to seal the outlet. 52 whereupon the uzfluid fed through pipe 1'4 will= further raise valve mem- ..;ber 17 thusincreasing 'the pressure of the fluid until i-.:the valve qnember' will uncover theperipheral groove 1: wherefrornthe oilwill now escape through duct 24,

,:46throughoutlet54l :On afurther-increase of the-speed, d3all 150 z'willoseal outlet'54 As a result, valve-member 17 will :be-.nfurther 1iftedthus increasingthe pressure epnevailing in*lline:14 .until 1the=valve member 17 i will -un- 1 .icovenitheioutlettport- 22 permitting the surplus oil to be .ctdis'charged. 1 55 ln:this mannerptheucontroller R is-operative to fix i-Kthe pressureprevailingin. line 14 to one of four different amounts: in:.dependence.on. the speed of travel of "the avehicle. t a

The function of the pressure step controller R is indi- ;cated in1Fig. 7.,I it being understood that the function so .farrdescribed: with. reference to Fig. 5 is obtained when leversl6 is.set tozffnormal. When the speed of the-vehicleis betweenzz'ero and. V1,.the four oulets 51, ;52, 53,; andi 54..are. t0pen andtherpressure'pl is practically zero. When the speed increases beyond V1, the closing ofvoutlet 511111CI621SBSl-l1h6 fluid pressure to p2. .When the. speed increases abeyond V2, :the closing of ;out-

- let 527increases'. the .fluidrpressure top3. When the speed increases-jbeycindiVS, the..oulet.'54 will. be closed raisin thepressure to p4. a

The functionof the controller R when -1eve'r 1"6; has .$been sjettorgbraking I? or.braking II? will be described drl ag a'ntshifttvalves.

. later-in connectionwith the functionof the pilot valves- I -peripheralcgroove 38, longitudinal duct 42, and chamber lheportion Q21of-;theconditioning valve Q is r-ilgidly connected with the portion Q1 andis provided with two spaced pistons and 61 slidably guided within a bore of the valve casing. A co-axial slide valve 63 provided with spaced piston sections 64, 65 and 66 is slidably accommodated in the same bore. houses a spring 62. This spring bears against an end shoulder of the bore which opens into the atmosphere and bears against the slide valve 63 tending to move the 7 same into the position shown in Fig. 5 in which the piston 65 bears against a stop 67 projecting into the here. The valve portion Q2 cooperates with internal grooves i 68, 69, and 70 provided within the bore and being so spaced as to be positioned between the piston 60, 61

when the valve Q is set to normal as shown in Fig. 5.

The groove 68 communicates via lines 71 and 72 with the pressure line 14 of pump P, whereas the grooves 69 and 70 are individually connected to pipes 73 and 74 leading to valves K3 and S4.

There are provided two pilot valves K2 and K3 and three gear shift valves S2, S3 and. S4. The gear shift valve S4 performs the additional function as a pilot valve. The valves K2 and S2 control the actuation of the ram II for the setting of the transmission to the second speed ratio. The valves K3 and S3 control the actuation of the ram III for the setting of the transmission to the third speed ratio. The valve S4 controls the actuation of the ram IV for the setting of the transmission to the fourth speed ratio.

Moreover, the valve housing includes a pressure controller T which controls the pressure fluid supplied from the pump P1 or P2 to the gear shift valves S2, S3 and S4 in the manner disclosed in my co-pending application Serial No. 320,032. Finally, the valve casing includes valves Av and V to be described later.

nected in spaced relationship by a valve stem. Pilot.

valve K3 comprises the spaced piston sections 77 and 78. The combined pilot and gear shift valve S4 comprises the spaced piston sections 79 and 80. Each of the valves K2 and K3 is urged towards its right hand end position by a spring 81, or 82 respectively, accommodated within the cylinder bore 83 or 84 respectively, in which the pilot valve piston'section of smaller diameter is guided. The end of the cylinder bore 83 is connected by a pipe 85 with the pressure pipes 14 and 71 of pump 1,

v the pressure therein being controlled by the pressure step controller R. The cylinder bore 84 accommodating section 77 of smaller diameter of pilot valve K3 is connected by line 73 to groove 69 controlled by conditioning valve Q. The cylinder bore 86 accommodating piston section 79 of the valve S4 communicates by a pipe 74 with the groove 70 controlled by valve Q. The valve S4 is urged towards the left end position shown in Fig. 5

by a spring 87 inserted in the cylinder bore 128 of larger diameter.

The spring 81 is biassed to a higher degree than spring 82. Therefore, valve K3 is urged towards the right with a smaller force than is valve member K2. In Fig. 5 valves K3 and S4 are illustrated in their left end positions, whereas valve K2 assumes its right end position.

The pressure controller T comprises -a stem 94 equipped with spaced piston sections 88, 89,, 90,91, and

92 andis urged. by a spring 93 towards the left, such spriugbeing inserted between an internal shoulder of the bore accommodating the valve and a washer adjacent to piston section 92.

; The stem 94 of valve Tdwhen moving fromtheposition shown in Fig. 5 towards the right, abuts against a diaphragm 95 within a housing 96 constituting a'vacuumco'nt'rolled actuator M. The interior of the housing 96 Moreover, the latter' "is divided by'the diaphragm into two'compartmen ts, the

one, on the left communicating with the atmosphere and combustion engine. Moreover, the housing 96 is provided with a sleeve 186 in which a rod 99 is slidably guided, such rod carrying a thimble 187 on its inner end, its outer end being connected by suitable motion-transmitting elements, such as a link 188, to the accelerator pedal 100 of the motor vehicle. A helical pressure spring 98 is inserted between the diaphragm 95 and the thimble 187 and will be tensioned by depression of the accelerator pedal100 beyondthe position shown in Fig. 5 which is the full'load position'in which the throttle is fully open.

Each of the piston sections 89, 90, 91 -and92 is adapted to control the communication of lines 129, 130, 131 and 132 with supply lines 112 and 123 in such a manner that continuous movement of valve member T to the left will successively cut 011 lines 132, 131, 130 and 129 in the manner described in my co-pending application Serial No. 320,032.

The slide valve Av controls the connection of a pipe 101 leading to the primary pump P1 geared to the ingoing shaft of the transmission with a pipe 102 to the cut 05 valve V. The latter is connected by a. pipe 103 with the secondary pump P2 which is geared to the outa going shaft of the transmission and which may be mounted on the'same shaft as the pump P. The valve V is composed of a cylindrical chamber encasiug two balls 104 and 105 urged apart by an interposed helical spring 106, the end faces of the chamber being provided with valve seats connected to the lines 102 and 103.

Moreover, the chamber has a port between its ends conconnected to further branch lines 116 and 117. Line 116 communicates with a groove 118 adapted to be controlled by piston section 76 of pilot valve K2. Pipe 117 leads to a control groove 119 adapted to be controlled by piston section 78 of valve K3. Moreover, branch line 120 connects line 109"with the pressure controller T, a branch 121 leading to the end space 122 of the cylindrical bore-thereof, whereas a branch line 123 leads to an internal groove 124., Communication of the latter with line 132 is controlled by piston section 92 of valve T. A branch line 125 leads from line 120 and branches 189 and 190 to the end spaces 126, 127 and 128 of the valve chambers of valves K2,f K3 and S4. 7

' The outgoing line 129 controlled by the pressure controllr-T'has-a branch 133 leading'to an internal groove 134 of the valve housing controlled by cylinder section -leads to an internal groove 152 of the bore accommodating valve member S2. The pipe 131 controlled by the pressure controller T leads to an internal groove 155 of the bore'accommodating valve member S31, Line 132 likewise controlled by -pressure controller T communicates through a line 191 with the lubricating point or points marked by the circleidenoted at Sch, and by line 1-36with the hydrodynamicclutch marked by the circle denotedat Hy. Moreover, line '136 is connected by a -branch 192 to the end space 137 of acylindrical bore accommodating valve member Av which comprises two cylindrical-sectional and 139 connected in spaced relationship by a valve' stem and accommodating ahelical ":i't Pfi lg 1 t d g murgethea ah member f valveAv IQ: he; po it n h n- E-When h @pr s re in the en space 137 overcomes that of spring;140, ;the .valve member Av isgmoved to the-leftguntil i ,ts :,cylindrical section 3 whereby. the surplus oil :jfed through line 136 will, be

1510116 of said valve,members,;being;-formed by two cylindn'cal seetions144; and;--145 ,connected in spaced rela- 1 discharged against they. pressuremaintained'by spring 7 140,- Just,gbeforethahhappens, howevenpiston section 138 has uncovered an internalgroove1142 likewise put on gy-exh-aust Q thus ,establishinga communication therewith 1 v(pf-pump .P1,-,;whereby the;pump P1is rendered inactive permitting valve ball 104 to be pressed on-itsseat.

;. Thegearashift;valve-S2:;comprises ;two,,valv e members I Slidably d d intai ylindrical bore otthe v l ei g,

tionship by a valve stem 143;-and ,=the other valve member roieomprisingra cup-shapedvalvemember146 having an ex- ;a-ternal groove 169, communicating-with the inner space 4-170 by .radial bores-,an d, in its ;;turn, accommodating a1 helica L pressure spring 147 tending to;move valve mem- -;.ber:-146 to;the;left-into engagement witha stem 193 integral with the other valvemembers143,144, 145. A

helicalqspring514$;surroundsstem 193 and tends to urge the two-valve, members-apart. The two valve-members ,control a plurality of portswhich will be described later .with reference to -the operati0n of the control system.

' The gear: shift valve S3 comprises a valve member ;slidably guided in acylindrical bore of the valve casing a and formed by two pistonsections 149 and 150 connected inspaced relationship by a stem andradapted to control the-alternativecommunication of an internal groove 156 with one or the other of two internal grooves 155 and 163.

- ,A spring .151 inserted in theend-space 167 of the internal bore tends to keep the valve member in its left end posi W tion: shown in,Fig. 5, while the twogrooves 156 and- 163 are put into mutual communication.

The line 130 controlled by. the-pressure controller T leads to an internal groove 152 ofgear shift .valve:S2. IWhen. the latter is inthe. positionshown, suchgroove communicates with a groove 153 which ,is connected with a line 154' leading to-the ram ILwhich ifactuated by fluid pressure ,sets the transmission to the second speed ratio.

' The line 131 controlled by the'pressure controller T is connected to the internalgroove 155 of valve S3, whereas the groove-156 ofthe latter is connected by a line 157 with the ram III which when fed by fluidunder pressure will set the transmission to the third speed ratio.

a The pilotandgearshiftgvalve S4 controls the alternative communication of a port 158.connected byline 159 to ram IV either with an internal groove 185 .connected to exhaust O, as shown in Fig. 5, or with the internal groove 134 which, as. stated heretofore, is suppliedwith 'fiuid under pressure controlled bypressure controller T 7 -via lines 129 and 133. Theram IV when actuated by fluid under pressure will set the transmission to its fourth speed ratio.

The-valvemember 63 coordinated with the conditioning valve Q controls a port 184, communicating with a line 160. In the position shown, valve 63 establishes a communication thereof with an internal groove 161 put on exhaust 0. 'When the valve 63 is depressed by valve Q coincidentally to the setting of lever 16 to synchronizing, port 184 will be put in communication with the internal groove 110 connected to line 109 as .de-

14 nale165 iofthetbore accommodating valve.'S2/:.;-Similar ---:n.1 ns :atiprorided to ensure; inacti-yation of a 111 P0 9 actua ion fTIr m'zIV-F :FOITi-Ih at-. nrpos.e,;iline".159 apply ng.-r msIvihasiahranehaineslsfi l adlngitflihecend 7yQaC5'1 67i of the boreglaccommodatingwalve S3, aibranch line 168conn ctingiline ltifi wi hea p t communicating .'W h:,-the1 xternal groove 169; f v v sm m 2 of valve S2. Pluid pressure suppliedtoyramiVgwillythus obtainaccess through lines 1166; andv'168, {groove 169 and radial ,bores to, the. interiorz space 147. of cup-shapedvalve v member ;146 'shifting the; same to'theleft.

From a.iporticommunicating withithespace .172-between pistonseetions 7 5 and;761 of pilot valve-K2, aduct datingr-gearishifhvalve S2.; Similarly, aport; communig catingwith the qgspaceffl between; .piston sections: 77

1 connected by a;duct 174 with j .arrinternal;groove;,176 of,-;the;bore accommodatingavalve :15 said-c 16: b i sp c d =fmm+ heyp rt of' l 2168 a distance, Jess; than the width of the external; groove 169a- A ,branch =,duct 17 7 -leads from. zlinev 174 to -the left q end space 175 of the,-l1or,e accommodating valve S3.

. Theaoperation of'the novel eontrol system is as-follows: Let us assume that-the control lever (not-shown) 1:,mounted 3 on thegsteering columnand cooperatively'con- ,nected with lever 16 isset'to its idling position indieated at a in Fig.;4thereby conditioning valve Q to the position-illustrated in Fig. 10...: Letus further. assume that the engine has been startedm Piston. section 60 of condi- :tioning. valve section Q2 is;positioned beneathinternal groove 68 putting lines 14; 71 and 72 in communication with exhaustgandreducing the pres-sure in lines 14, 71 ,4 and; 72 to atmospheric. pressure. Super-pressure .valve U rernains in itsdowermost -position shown in Big. 5,, Pilot the same being the right hand end position. wPilottand valve K2 likewiseassurnes -th-e position shownin Fig. 5,

gearyshift'yalve S4 is kept :byspring 87 in its leftend position as shown, -.becau'se linev 74 communicating-with q :the end-space 86of-valve S4 is -put,. onexhaustviaethe internal groove .161,;-the:pistonsection 61 ofconditioning mvalvesectiont Qlbeing-depressed to a position beneath the upper edge of groove 161. For .the :samereason -llne 73is .put on. exhaust.

Whentheengine is idling-,the pump. P1 driven by the engine produces pressurecommunicated .via 101,102, V,

. 107,-108, 120,. 125, 189- and .190 to. theendspaces. 126

and 127 ofthe pilot valves K2 and K3,- whereby the 'valve members of the samewill be urged to the. left contrary to the tendency of their springsv 83 and.84.

The pilot valves ofthecontr'ol systemare now conditioned to cause actuationof ram II to set the transmission to the second, speed ratio. The valve 63, which as stated has been depressed. by the conditioning valve Q,

, .puts line; 11,1 leading to a port located betweenpiston pilot 'valve K2 establishes communication betweengroove 118 connected to, line 116 and a port connected to line sections 66. and 65 incommunication'with peripheral groove connected to a line 180 leading to exhaust. :Since 171, the following connection is established: Liner-180 establishes {the following communication: Groove-181' connected to the, atmosphere, line 111, line 116, groove 1 113, space 172, ,line 171, and endspace 173 of valve. S2. Therefore, spring148 will move 1thevalve section including pistons 144and 145 to thedcft. Pilot valve K3 connected to exhaust,=space 175, line 174,,and endspace .177 of gear; sh-iftvalveS3. Therefore, springj151-will ,keep valve-S31inthe resting position shown in .Fig. .5. As 'a result;1tl1e rams. II, III and IV are connected to exhaust, linesf129, and 131'being connected to exhaust via. 111, 112,; 114;;and 1 15; The ram'flI of the first gear is .-likewisej onexhaustviav line" 135,. line '129, e'peripheral groovee114 of;pressurecontroller T, line 1:12,

line 1111,- and line 180.

'Whenthe :drivenwishes to .startz-ther vehicle, he must shift the.=c'ontrol. lever:.(no.t shown) ZIIlOllIltCdILOH...-th

steering column to the position normal shown in Fig. 4 thereby movinglever 16 to the position normal shown in Fig. 5 bringing the conditioning valve Q to the position shown in Fig. 5. Fluid fed by the primary pump P1 is fed via lines 101 and 102 to the valve V lifting 5 valve V the pressure fluid is fed through line 107, filter l0 108, line 109, groove 110, and lines 111 and 112 to the pressure controller T whence the pressure oil is admitted to the lines 129 to 132. Moreover, the pressure oil is admitted from line 111 through lines 113 and 116,

groove 118 and port 172 of the pilot valve K2 and through duct 171 to the pressure space 173 of the gear shift valve S2, whereby valve S2 is shifted .to the position shown in Fig. 5. As a result, the gear shift valve S2 admits pressure fluid from line 130 via grooves 152 and 153 and line 154 to ram II setting the transmission to the second speed ratio. As soon as the vehicle attains a certain speed causing pump P2 to produce sufiicient pressure to lift valve ball 105 from its seat, the control system will now be supplied with pressure fluid from the secondary pump. When the pressure oil is fed from filter 108 via lines 120 and 123 to groove 124 and thence past piston section 92 to lines 132, 136 and 192, the pressure therein will shift valve Av in the manner described thereby putting lines 101 and 102 on exhaust and permitting spring 106 to press ball 104 on its seat. 330

While the lines 112 and 113 connected to line 111 and the ducts and valve spaces communicating therewith are controlled'by the conditioning valve Q and by the valve 63, the lines 120, 123 and 125 communicating with p the filter 108 are independent of the conditioning valve Q. The pressure controller T is subjected to the pressure in the associated end space 122 connected to lines 121 and 120 which are thus independent of the setting of lever 16. Similarly, the supply of oil under pressure to the hydrodynamic clutch line 136 and the supply of j line154 toram II.

lubricating oil through line 191 are independent of the setting of lever 16. L

The valve Av acts as an over-pressure valve limiting the maximum pressure. When the pressure in space 137 to disable pump P1 as soon as pump P2 is able to supply the required fluid under pressure.

The pilot valves are subject to'the pressure controlled by the pressure step controller R and are thereby enabled to respond to an increase of the vehiclespeed beyond the speed limits V1, V2 and V3 as described here- &

inabove.

The pressure controller T, which as stated above is acted upon by the pressure in space 122, is subject to the pressure of spring 93 and toad additional pressure the diaphragm depends on the vacuum in the intake manifold of the engine communicating through pipe 97-with the diaphragm chamber, and on the bias of spring '98 produced when the accelerator pedal 100 is kicked down beyond its fun gas i in which an? thrdme fully whereby the transmission, will be operated .at the first I speed ratio,'since ram l-is being supplied with fluid under pressure via lines 129 and 135, "and since the gear clutched to the driving shaft :by thetoothed clutch actuated by ram I acts on the outgoing shaft of the transmission via a oneway clutch. Movement of pilot valve K2 to the left causese'nd space 173 of: gear shift valve S2 to beput on opened. The dependence on the vacuum of the machine has the effect that piston section 92 will throttle the flow of fluid from pipe 123 to pipe 132 more or less thus maintaining in lines 123, 120, 125, 189 and 190 a pressure substantially corresponding to the torque produced by theengine as thevacuum in the intakeiofthe engine is proportional to the torque produced by ItheTengine. In this manner, the pilot valves K2, K3 and S4 are controlled in dependence on the torque'produced by the en- Igine :thus being able to determine the .shifting-upfdim 75.

gram of the control system and, at the same time, the pressure produced in the friction clutches of the transmission' by the rams. p p

A continuous displacement of the valve member of pressure controller T to the right will successively open lines 130, 131, 129 and 132, line 130 supplying ram II, line 131 supplying ram III, line 129 supplying rams I and IV, and line 132 supplying oil for the lubrication points Sch and for the hydrodynamic cltuch Hy. For a detailed explanation of the function of the pressurecontroller reference may be had to my co-pending application Serial No. 320,032.

The maximum pressure supplied to the rams is controlled by valve Av as described hereinabove.

.The pressure spaces 126, 127 and 128 of the pilot valves K2, K3 and S4 are supplied by the primary pump a P1 or the s'econdarypump P2 directly via lines 120, 125,

189 and 190. Therefore, the function of the pilot valves is independent of the setting of the conditioning valve Q. The pressure spaces 83, 84 and 86 of the pilot valves are supplied with fluid under pressure controlled by the pressure step controller R, such pressure thus depending on the speed of the vehicle. V

The springs 81, 82 and 87 of the pilot valves are so dimensioned and biassed as mentioned hereinabove that when the fluid pressure amounts to p1 (Fig. 7) it holds pilot valve K2 in its operated right hand position shown in Fig. 5 thereby causing fluid pressure to be supplied to ram 11 in the manner to be described hereinafter, irrespective of the pressure maintained by pressure controller T in space 126 as long as accelerator pedal is not kicked down. The pilot valve K2 in its operated position establishes a communication from valve V via line 107, filter 108, line 109, groove 110, line 111, line 113, line 116, groove 118 controlled'by pilot valve K2, space 172 of the latter, line 171, and end space 173 whereby gear shift valve S2 is urged to the position shown in Fig. 5.

This valve establishes a communicationtrom line 111 via line 112, groove 114, groove 182, duct 130, groove 152 of gear shift valve S2, gr0ove 153 of the latter, and

When the speed of the vehicle increases beyond speed V1, the pressure step controller R raises the pressure in line 71 to p2 (Fig. 7) in the manner described. As a rises beyond a certain level, the primary pump P1 is first '45 result, pilot valve K2 will be maintained in'the position shown in Fig, 5, even should pressure in space 126 be in- V creased'by the driver. kicking down acceleratorpedal 100.

Should the pressure maintained in lines and andin space 127 of pilot valve K3 by the pressure controller T in dependence on the intake vacuum drop below a value corresponding to the curveDE in Fig. l, or i should the speed of the vehicle exceed the limit V2, the 7 pilot valve K3 will be shifted to the right under the com- 1 bined etfect of spring 82 and of the fluid pressure set up by pressure step controller R in lines 71 and 73and in space 84, However, by kicking down the accelerator pedal 100 beyond its full power position, thedriver may increase the throttling efiect of piston section 92: and

. p h may thereby .raise the pressure prevailing in lines 123, exerted by the diaphragm 95. 'The pressure exerted by 0 125 and 189 and in space 126 to such an extent as to cause II; from pressure inthe manner describe-dhereininafter,

exhaust via1171, 172, and aggroove 183 connected to exhaust 0. As a result, pistonfsections 144 and 144 of gear 'shift valve S2.are. moved by spring 1 48 to theleft putting assume 117 ram III- on exhaust via :1ine;.1.54,rs s2 v i153,.-g oov .162, line ei-groove 18,4, groove 115 ,10-

-The following operations occur when the ;transmission is shifted from the second speed ratio to the third speed ratio: Shifting of the pilot valve ;K2 to its right hand end position shown in Fig. 5 establishes communication of the primary or secondary pump via 111, 113, 116, 118,-and 172 with the line 171,'whereby pressuresis ShPPlied to the end space 173 shifting gearshift valve {S2'to the-position shown in Fig. 5. The space :165 of gear shift valve S2 is put on exhaust via line 1164, groove 1 56 of gear shift valve S3, groove 163 of the same, line lth'groove' 184, and groove 161 End space'17t) of gearshift valve S2 is likewise put on exhaust viagroove 169,, lines 168, 166 and 159, port 158 of valve S4, and groove 185 of the latter which is connected to exhaust O. Therefore, Valve S2 is kept in its right hand position shown permitting pressure oil .to besuppliedfrom line 112 via groove 114 of pressure controller T, line 13.0,,grooves152 and,15,3, and line 154 to ram II.

Asstated heretofore, an increase of :theyspeed of the vehicle beyond the limit V1 causes the ball 47 of the pressure step controller R to increase the pressureto 122. If at that time the transmissionhad already been shiftedto the second speed ratio, and if-the power output of ,the transmission exceeds N3 (Fig. 1), the pilot valve K2 assuming its right hand end ;position, the increase of-the fluid pressure to p2 has the soleelfect that the driver can no longer shift the transmission back to the firstspeed ratioiby kicking down the accelerator pedal thereby increasing the pressure in space 126 beyond the normal maximum pressure.

At the same time, however, the pilot valve K3 is put in condition for operationbeing ready to move to the right as scenes the vacuum-controlled pressure in the end space 127 drops below-a certainlimit. ;;In;that instant, the pilot valve K3 is shifted to the right whereby thepressure fluid having a pressurecontrolledby the :pressure controller T is admitted via the pipes 111,113 and '11-7, groove 119, space 175, line 174, and 11115117710 the pressure space 1780f the gear shift valve-S3 thereby shifting the same to the right. As a-re'sult, the fluidzunder pressure controlled by the pressure controller T will be admitted via line 131, groove 155,;groove156, and line 157 to the ram III thus setting;the ;transmission,;to:the thirdspeed ratio. Fromgroove .156 pressureifluid is admitted through line 1614 into the.- space 1650f valve -,S, 2 thereby shifting the valve member provided with piston sections 144 and 145 to the left. That has the effect'of puttingram II on exhaust in a' manner describedheretofore.

When pipe 131 is opened by piston section 91 of the pressure controller T, the sudden admission of fluid under pressure to ram III causes a drop of pressure inend space 122 tending to move the pressure controller'T to theleft whereby the admission to line131 is throttled to such an extent as to maintain in lines 121 and 120 the pressure determined by the-intake-vacuumof the engine. ,Line 130, however, is kept open, whereas -line129 supplying ram 1 and ram IV is temporarilyv closed by piston section 89. As described in my co-pending application, that has the effect of delayingthe supply or fluid under pressure to ram I until after ram II has been suppliedwithpressure fluid. That in turnhas the etfectof synchronizing the toothed clutch elements actuated by ram'I.

Maintenance of the pressure by the pressure controller T keeps the transmission set to the second speed ratio until a certain minimum pressurerhas been built up in ram III. Only after such minimum pressurehas beenreached and has been transferred via groove 15,6 and line 164 to space 165 of gear shift valvelslwlll ram' III be, actuated and gear shift valve S2 restored'tothe leftjtotherebvrelieve ram 11 from, pressure. The ,itimed overlapping of theactuation'of rams'II andI'II ensures that the, transfer of power through the transmission will not be interrupted.

acti g 0 .11 .e' c v -d ttsteht al areao-fthetwo cro It h s bee a sumed 1h reitIah wth the :trahsmi ion is shifted to the thirdspees :r t y d op tQ 1h power output below curve N3 in Fig. 1. However, the same sh t n p a on o h t a sm si oc r whenthe speed of the vehicle exceeds the-limitVZ at a timewhejn the power output is above the values defined by the litle NZi. In thatevent, the pressure'prevailing in space 84 of pilot valve K3 will be increasedfby the pressure step; controller R-to the amount p3 overcoming theptessure prevailing;in space 127 therebyshifting-thepilot valve K3 to the :right causing gear shift valve S3 tobe likewise shifted'to :the right, whereby pressure oil will be Supplied to ram I151 inthe manner described. (I

When the vehiclespeed-exceeds' V3, the pressure prevailing inspace 86 ofipilotvalve S4 is'inereasedto the value P gby t p l valv L is shift d 1 .0fm? right. As a result, fluid under pressure controlled ;by th je pressure controller I is admitted from line ;129 via;l ine 133, -groove134, port 158,;and line 159 toram IV setting the transmission to the fourth speed ratio. The same shifting operation may occur While the speed of the .vehicle is between'the limits V2 and V3 provided meme intake vacuum-of theengine reduces the pressure .prevailing in the endspace 128 of valve S4 to an amount corresponding .to a power output lower than the curve H-I.

,C-oincidentally to the actuation of ram I'V'fluid under pressure is supplied from line 159 via line 166.to pres-sure space 167 of-valve S3 and through branch pipe 168 and groove 169 to pressure space 170 of1valve'S2. Thishas the effect of locking valve 82 in its left end position, as described in detail in .my co pending patent application Serial No. 320,032. Moreover, it has the effect of re.- storing valve S3 to the position shown as :soon -as sufficient pressure has been built up in tram IV :to cause actuation thereof. Such pressure will shift gear shift valve S3 to the position shown contrary to thetendency of the pressureprevailingin space-178.

When the-speed of thevehicle ldrops, the fiy-weights 47, 48, 49 and 50 will be successively restored to their resting position .the-reby. stepwise reducing the pressure. :However, suchreduction will notoccur when the speed passes through thelimits V3, V2 and V1, but it will occur when the speed passes-through slightly lower limits V3, V2 and V1;

Thatis sogbecause the balls, after having sealed ethe outlets 51, 5-2, -5 3;and 5.4, are not only subject :toethe centrifugaljforce but 1 are subject to the additional Runba'lanced ffluidpressnre prevailing in the chambers .43, 44,315, and '46. Thereforewhen thespeed of .the vehicledrops, thesprings .56, 57, -58-1and- 59 must ,overcome noLo'nly the centrifugal force but the additional unbalancedfiuid pressure. They are not able to do ;so :untilthe speed passes through-the lower limits V3, V2? and $1.1.

:When the-speed ofthevehicledrops, the shiftin'gdown operation will not occur until ,the speed passes through the speed limit. If the transmission has been :set-to its fourth speedratio for instance, itwill not beset tothe; third speed ratio automatically as long asthe speed exceeds V2, irrespective, of thepower output pf the engine ,and of t n k asuutn cont ol i sutepr a nsintspace 87. Therefore, thecondition ofoperatiomof the vehicle withthe transmission .set ,to ,any particular ,ratio, f r; instancetothefourth speed .ratio, maybe determine Fig. 1 by a point located above line N4,;provide such pointjs reached afterrthe vehicle '.was operated; reviously under a condition representedby sp rm located within areaG.'H-'I.. LM. This eifect' isattained by the function of the pilot valves as differential pistons. Once a pi1ot ,valve, such as valve S4, has been shifted to its operative right handposition, the pressureprevailn v in the a d sa 1 1 w ms astr h th .j'p'r i re P in w enih fi o Pi to sec 3 s3 tions f .79 and .80. When the releases restoration of the pilot valve S4 because the spring 87 is counteracted by the differential pressure between piston sections 79 and 80. In that respect, the function diifers from that occurring in the shifting-up operation in which the pilot valve S4 remains in its left end position keeping the transmission shifted to the third speed ratio as the pressure step controller R maintains the pressure on the limit p3. Of course, the driver if he wishes may nevertheless shift the transmission from the fourth speed ratio to the third speed ratio while the vehicle speed is between the limits V2 and V3, or V2 and V3 respectively, by kicking down the accelerator pedal all the way, whereby spring 98 is given an additional bias increasing the throttling effect of piston section 92 and raising the pressure prevailing in lines 123 and 125 and in the end space 128 beyond the normal amount thus enforcing a restoration of pilot valve S4 in a manner similar to that described with reference to the shifting of the transmission from the second speed ratio to the first speed ratio. Similar considerations apply to the shifting from the third speed ratio to the second speed ratio.

Now the operation of the novel control system will be described when conditioned for the operation braking I, as may be desirable for driving in city traffic. With that adjustment, the groove 70 of the conditioning valve Q is disconnected from pressure pipe 72 and pump P and is put on exhaust via a discharge port 194. Therefore, the end space 86 of the pilot and gear shift valve S4 connected to' the groove 70 by duct 74 can no longer be subjected to fluid pressure, and the valve S4 can no longer be moved to operated position but will keep ram IV de-energized.

Groove 20 controlled by the superpressure valve U is now put by conditioning valve section Q1 into communication with the duct 32 and thus via groove 37 and longitud'mal duct 41 with the chamber 45 of the pressure step controller, whereas in the normal condition of valve Q2 the groove 20 was in communication with chamber 44. The spring 58 coordinated to chamber 45 is so biassed, however, that the ball 49 seals the associated outlet 53 at a speed V2x which is higher than the speed V2. Therefore, with the control system conditioned for braking I, the pressure step controller will not raise the fluid pressure in lines 14 and 71 to the amount p3 until the higher speed limit V2x has been reached. as illustrated in Fig. 8.

Hence, the transmission will be kept set to the second speed ratio up to a higher speed of the vehicle as is desirable for city traihc. same as described for norma When the control system is conditioned for braking II by suitable adjustment of lever 16 and conditioning valve Q, the groove 69 will be put on exhause via groove 194 and thereby the end space 84 of the pilot valve K3 will be relieved from pressure via duct 73 and the groove 69. As a result, the two rams III and IV will not be energized and the transmission can be set to either the first speed ratio or the second speed ratio only, as shown in Fig. 3.

The valve section Q1 establishes a communication between port 19 and port 31 in the pressure step controller R. As a result, the pressure prevailing in lines 14 and 71 will not be raised from pl to p2 until the speed of the vehicle exceeds the limit V2 causing ball 48 to close the outlet 52. While the pressure may be raised beyond 122 by the pressure step controlled when higher speeds are attained, such increase of the pressure will not have 3 efiect because the pilot valves K3 and S4 have been inactivated in the manner described. When the dri l' Otherwise the function is the 1 shifts his control lever mounted on the steering column into fReverse" or into Parking, lever 16 by its connection with such control lever is temporarily rocked into the position Reverse (which is indicated in Fig. 5 as the highest position) whereby the stem of valve Q is depressed to its lowermost position and acting on valve 63 moves the latter down until it establishes a communciation between line 160 and groove 110. This has the effect of a simultaneous actuation of rams II and Ill whereby the driven member of the hydrodynamic clutch and the transmission elements geared thereto are brought to a full stop preparatory to the shifting of the reversing gear into mesh or preparatory to the engagement'of the parking locking member. Such simultaneous actuation of rarns II and III is eifected by the establishment of a connection of line 107 via filter 108, line 109, groove 110, space between piston sections 65 and 64, line 160, grooves 162, 163 and thence, since the valves S2 and S3 are in their left end positions, to the rams II and III. When lever 16 returns to Idling, piston section 65 closes groove again and the uppermost piston section 66 of valve 63 uncovers the groove connected to exhaust 0, thereby relieving line from pressure and de-energizing rams II and III causing disengagement of the friction clutches actuated by such rams.

Hereinafter the conditions will be recapitulated which result in the described actuation of the pilot valves.

p1, p2, p3 and p4 define the fluid pressures as shown in Figs. 7, 8 and 9.

f1, f2, f3 define the pressures exerted by springs 81, 82 and 87.

pul, pu2, m3 define the pressures which, if applied to the end spaces 126, 127, 128 of the pilot valves, will produce the shifting operation prescribed by the boundary lines, such pressures depending on the driving torque.

p-Min defines the smallest controlled pressure (basic pressure).

p-Max defines the largest controlled pressure with fully opened throttle of the engine.

pu defines the super-pressure produced in spaces 126, 127, 128 by kicking down the accelerator pedal.

k defines the smaller cross sectional area of the piston sections 75, 77 and 79, and

k1, k2, k3 define the cross sectional areas of the larger piston sections 76, 78 and 80.

The operation of the pilot valve K1 for the second speed ratio is controlled by the following conditions:

as condition for the shifting operation under conditions defined by a curve N1, N2 or N3 in Figs. 1, 2 and 3;

as the condition excluding an automatic shifting-down operation without a kick-down of the accelerator pedal;

as a condition ensuring the shifting-down operation produced by a kick-down of the accelerator pedal;

as a condition ensuring that with the increased fluid pressure pul, pu2 or p113 even a kick-down will not produce a shifting-down operation from the third speed ratio to the second speed ratio, and that with such a kickdown there will be a shifting-up operation from the second to the third speed ration;

as a condition preventing the actuation of the pilot valve of the next higher order as long as p1 is effective. Similar conditions apply to the other pilot valves.

. From the foregoing it will be readily understood that my novel control system comprises the following basic elements: 7 r I ,A first means, in the present embodiment in form of any l-2'1 one of the pilot valves K2, Ks/ and s4, adapted when actuated by fluid pressure to shiftsthetransmissionifrom the first to the second ratio, or from the second to the third ratio, or from the third'to the fourth ratio respectively;

A second means, in the present embodimentin form of the valve T, influenced by diaphragm 95 substantially in proportion to the driving torque exerted uponthe transmission by the engine of the motor vehicle. By vcontrolling the pressure in lines 123, 125, 189 and190 the valve T is adapted to cause actuation of said first means, i. e. of each of the pilot valves K2, K3 and S4;

A third means, in the present embodimentin form of the pressure step controllerR, controlled bythe speed of the vehicle and adapted bycontrolling the pressure of the fluid admitted to spaces 83, 84 and 86 to likewise cause actuation of said first means K2, K3 or S4; and

Means, in the present embodiment formed by the'valve 63, rendering said second means T operative betweena lower limit and an upper limit of the vehicle speed, such as V2 and V3, to cause actuation of said first means, e.-g. K3, in response to a change of the engine torque. Beyond the upper speed limit, such as V3, the third means, to wit the pressure step controller R, is operative to enforce actuation of said first means, suchas K3, ir respective of the condition of T,.i. e. irrespective of the torque produced by the engine. As a result, the transmission will be shifted from the third ratio to the fourth ratio or, broadly speaking, from a certain ratio to the next higher ratio, automatically between said speed limits V2 and V3 in dependence on the engine torque. But the transmission will be shifted at any rate when the vehicle speed exceeds said upper limit, such as V3, no matter what the engine torque at thatvtimemight be.

While I. have describeda preferred embodiment of'my invention, I wish it to be'clearly understood that the same is not limited to the details of such embodiment, but it is capable of numerous modifications within the scope of the appended claims.

What I claim is:

1. in a control system for a motor vehicle transmission. the combination comprising a source of pressure fluid, a relief valve member subjected to the "fluid pressure ofsaid source and adapted when movedby'said pressure to successively uncover a plurality of relief ports, a plurality of discharge ports rconnectedito respcctiverelief ports, a spring acting on said :valve member in opposition tosaid fluid-pressure, and means responsiveto therateof travel of said vehicle and adapted-as'said'rate increasesto successively prevent flow of saidfiuid through said discharge ports to thereby increase said pressure step by step.

2. The combination claimed in claim -1 in which said means responsive to the rate of travel of the vehicle comprises a .centrifugal governor-havinga plurality o'ffiyweights, each fiyweight controlling one of said discharge ports, and springs beingvindividually coordinated'to-said flyweights and being differentially biassed thereby rendering said fiyweights responsive to different speeds.

V 3. The combination claimed inclaim l in which said means responsive to the'rate of travel of the vehicle comprises a rotary member'having 'eccentr'icaliy located valve chambers'each provided with an externaldischarge opening, balls encased in said chambers and adapted under the effect of a centrifugal force to close'said openings, said balls and said springs being 'so difierentially. proportioned as to be responsive to different rotary speeds.

'4. A control system for-a motor vehicle transmission adapted to be set to any one of a plurality of ratiosof transmission, comprising first means operative uponzactuation' thereof to control the shifting of said transmission from one of said ratios to "the nextjhigher one ofvsaid ratios, second means operative by the intake manifold vacuum 'arrd'proportional at least in part essentiallylin dependence on the'driving torque exerted byt th erengine of :22 the-motor -vehicle uponlsaid transmission-1andnadaptedfto cause actuationof said firstmeans,thirdrmeansscontrolled by the speed of the-vehicle.aad adapted to likewisecause actuation of said first meansgand meansgrenderingisaid second means operative between arlower ,limit and an upper limit .of said speed "to cause-actuation of saidafirst means in responsetoa. change of said vacuum and therewith of said torque, said third means being toperative beyond said upper speed limit to enforce actuation of said first means irrespective of thecondition of said .second means, whereby the shifting of: thetransmissionfrorn said oneratio to the next higher .rationis automatically effected between saidspeed. limits in dependence-ionlsaid vacuum and therewith of said torque andtthe transmission is thus shifted to said next -.-higher ratio when the vehicle .speed exceeds said upper .limit irrespective 10f said torque.

5. A controlsystem as claimed in claim 4, Wher'einssaid first means is operative .uponrestoration-to normal" to control the shifting oftsaid transmission back-from said next higher one of said ratios to 'saidifirst-mentioned one, said second means being unable to cause-restoration of said first means while said thirdmeansis :operative below said lower speed limitto enforcerestoration OfrSEid first means irrespective of the condition of said second means, whereby the transmission will be shifted back from 'the higher speed ratio to the next lower speed ratio-irrespective of the torque of the engine, whenth'e sspeed drops below the lower one of said limits.

6. YA control system as claimed inclaim 4,'wherein said first means is operative upon restoration to normal to control the shifting of said transmission back from'said next higher one of said ratiosto said .first-mentionednne, said second means .being unable to .cause;restoration-of said first means while said: third, means is operative :below said lower speed limit tocnforce restoration .o'f-tsaid first means irrespective of the condition of saidI-secondrmeans, and further comprising-fourth means arbitrarily-operable by the driver to enforce upon'actuation thereofrestoration of said first means, whereby;the.transmissionzzwill'ibe shifted back from the higher-speed ra'tioto thex next lower speed ratio, irrespective of the torque of theeengine, either when the speed drops below the lower one ofisaid limits or when the driver arbitrarily operates saidfourth means.

7. The combination withacontrol system;f'or':a mn+ tor vehicle transmission adapted toibe. set to 'any one of a plurality of ratios oftransmission of';settable,meanssseb table bythe driver and operative :to condition said con-'- trol system to any one of three ranges. having aplurality of transmission ratios with at least two ratios defining each range, said system includingmeansaoperative in one of said ranges to automatically;shiftxsaid transmission to any one of said plurality of ratios, operative insa second one of said ranges to automatically shiftsaid transmission to any one'of a number of ratios-.smaller than said plurality, and operative in the third :one ofsaidrangesto automatically shift said transmission tOflIlY'OIlC. of a number of ratiossmaller than said last-mentioned number.

8. The combination as claimed inclai-m 7, wherein said control system comprises first means operative upon actuation thereof to controlfshifting'of saidttransmission' from one of said ratios to thenexthig'her one of said ratios, second means operative by the intake manifold vacuum and proportional at. least in part substantially independence on the driving torque exertedbythe engine of the motor vehicle upon said transmission and adapted to cause actuation wofsaid first means, third-.means controlled by the speed of the vehiclevand adapted. toliklewise cause actuationof said first means, and, means, rendering said second means operative ,betweemalower limit and an upper limit of said speed .to causeactuationriof sai'd first means inresponse to achangeof said-vacuum land. therewith 'of sai d :-torque, of saidt.third;means being operative beyondsaidnpper speed limit .tozzen-forceiactuaa tion of said first meansirrespective v tpfnthe,cou'dition:ofi

menses 23 said second means, and said settable' means being operative to control said third means so as to raise said upper limit of said speed in said second range and in said third range as compared to said first range.

9. A control system for a motor vehicle transmission adapted to be set to any one of four ratios of transmission, comprising first means operative upon actuation thereof to control shifting of said transmission from one of said ratios to the next higher one of said ratios, second means operative by the intake manifold vacuum and proportional at least in part substantially in dependence on the driving torque exerted upon said transmission by the engine of the motor vehicle and 'adapted to cause actuation of said first means, third means controlled by the speed of the vehicle and adapted to likewise cause actuation of said first means, means rendering said second means operative between a lower limit, an intermediate limit and an upper limit of said speed to cause actuation of said first means in response to a change of said vacuum and therewith of said torque, said third means being operative whenever the speed exceeds one of said limits to enforce actuation of said first means, and settable means arbitrarily settable by the driver and operative to condition said control system to an abnormal condition to thereby disable said first means to control shifting of said transmission from the third ratio to the fourth ratio, said settable means being further operative to control said third means to raise said intermediate speed limit.

10. Control system for a motor vehicle transmission adapted to be set to any one of four ratios of transmission, comprising first means operative upon actuation thereof to control shifting of said transmission from one of said ratios to the next higher one of said ratios, second means operative by the intake manifold vacuum and proportional at least in part substantially in dependence on the driving torque exerted upon said transmission by the engine of the motor vehicle and adapted to cause actuation of said first means, third means controlled by the speed of the vehicle and adapted to likewise cause actuation of said first means, means rendering said second means operative between a lower limit, an intermediate limit and an upper limit of said speed to cause actuation of said first means in response to a change of said vacuum and therewith of said torque, said third means being operative whenever the speed exceeds one of said limits to enforce actuation of said first means, and settable means arbitrarily settable by the driver and operative to condition said control system to a first abnormal condition, said settable means being also cperatively connected with said first means to disable said first means in said first abnormal condition to control shifting of said transmission from said third ratio to said fourth ratio and being operatively connected with said third means to be operative in said first abnormal condition to control said third means so as to raise said intermediate speed limit, said settable means being further arbitrarily settable by the driver to condition said control system to a second abnormal condition, said settiable means being also operatively connected with said first means to disable said first means in said second abnormal condition to control shifting of said transmission from said second ratio to said third ratio and from said third ratio to said' fourth ratio and being further operatively connected with said third means to control said third means so as to raise said lower speed limit in said second abnormal condition.

11. A control system as claimed in claim 4, wherein said first means is operatively connected with said second means and said third means to make avlailable within any range of speeds two ratios of transmission only, the upper speed limit of the range for the first transmission ratio substantially coinciding with the lower speed limit of the range for the third transmission ratio, and the upper speed limit of the range for the second transmission ratio substantially coinciding with the lower limit of the range for the fourth transmission ratio.

12. A control system as claimed in claim 4, wherein said first means is operative upon restoration to normal" to control shifting of said transmission back from said next higher one of said ratios to said first mentioned one, said second means being unable to cause restoration of said first means, whereas said third means is operative when said speed drops below a limit slightly lower than said lower speed limit to enforce restoration of said first means irrespective of the condition of said second means, whereby the transmission will be shifted back from the higher speed ratio to the next lower speed ratio, irrespective of the torque of the engine, when the speed drops below the lower one of said limits.

13. A control system as claimed in claim 4, wherein said second means is operative to cause actuation of said first means between said speed limits in response to an increase in vacuum and therewith to a reduction of said torque, provided the engine is able to produce the same power output at the next higher speed ratio.

14. A control system for a motor vehicle transmission adapted to be set to any one of a plurality of ratios of transmission, comprising a set of valves operable by fluid pressure, each operative upon actuation thereof to cause said transmission to be shifted from one of said ratios to the next higher one of said ratios, conduits supplying actuating fluid to said valves, a source of pressure fluid, a pressure controlled operative to connect said source to said conduits and to control the pressure therein, means operative by the intake manifold vacuum and proportional at least in part substantially in dependence on the driving torque exerted upon said transmission by the engine of the motor vehicle to adjust said pressure controller thereby causing the latter in response to a decrease of said vacuum and therewith to an increase of said torque to vary the pressure in said conduits in a manner causing actuation (of one of said valves, and a pressure step controller geared to the outgoing shaft of the transmission and operative to adjust said fiuid pressure to any one of a plurality of rates depending on the speed of the vehicle, and ducts connecting said pressure step controller to said valves thereby causing at least one of the said valves to be shifted, irrespective of the condition of said pressure controller, whenever the speed of the vehicle exceeds certain limits.

15. A control system for a motor vehicle transmission of the type settable to any one of a plurality of ratios of transmission by the individual actuation of one of a plurality of fluid-operable rams, as claimed in claim 14, in which the ram for the lowest speed ratio is supplied with fluid under pressure by a fluid line controlled by said pressure controller and adapted to supply fluid under pressure to the ram of a higher speed ratio under the control of one of said valves, said fluid line bypassing said one of said valves.

16. A control system for a motor vehicle transmission of the type settable to any one of a plurality of ratios of transmission by the individual actuation of one of a plurality of fluid-operable rams, as claimed in claim 14, further comprising a manually settable valve operative when set for idling to relieve said rams and said ducts from pressure without afiecting the pressure, which prevails in said conduits and is controlled by said pressure controller and acts on said valves.

17. The combination as claimed in claim 14 in which said source of pressure fluid comprises a pair of pumps arranged in shunt, one pump being geared to the ingoing shaft of the transmission and the other pump being geared to the outgoing shaft of the transmission, each pump being provided with an outlet controlled by a check valve.

18. A control system as claimed in claim 14, wherein in which said source of pressure fluid comprises a primary pump, a secondary pump, both pumps arranged in shunt, check valves coordinated to the outlets of said pumps, and a relief valve coordinated to said primary pump and operable by pressure produced by said secstresses ondary pump whereby pressure produced by ,said secondary pump will disable said primary pump. g P

' 19 A control system as claimed in claim 14, further comprising a manually operable conditioning valve operative to selectively connect said pressure step controller to said valves and to be set to at least one abnormal condition in which at least one of said valves is disconnected from said pressure step controller.

20. A control system as claimed in claim 4, wherein said third means comprises a source of pressure fluid, a spring-controlled relief valve movable by the pressure of said fluid and operative to control a plurality of discharge ports, and a rotary valve mechanism geared to the driven shaft of the transmission and operative to control said ports in dependence on the speed of the vehicle.

21. A control system as claimed in claim 14, wherein each of said valves is a pilot valve mounted to be movable by the opposed fluid pressures supplied through said conduits and through said ducts.

22. A control system as claimed in claim 14, wherein each of said valves is a pilot valve mounted to be movable by the opposed fluid pressures supplied through one of said conduits and through one of said ducts, said control system further comprising a plurality of fluid-operable rams, each ram being operative upon individual actuation thereof to set the transmission to a correlated transmission ratio, the ram of the highest ratio being controlled by one of said pilot valves, and gear shift valves individually connected to and operative to control the rams of the ratios other than the highest ratio and controlled by the other ones of said pilot valves.

23. A control system as claimed in claim 14, further comprising a plurality of fluid-operable rams, each ram being operative upon individual actuation thereof to set the transmission to a correlated transmission ratio, the ram of the highest ratio being controlled by one of said pilot valves, gear shift valves individually connected to and operative to control the rams of the ratios other than the highest ratio and controlled by the other ones of said pilot valves, and fluid lines controlled by said one of said pilot valves and by said gear shift valves connecting said rams to said pressure controller, whereby the pressure supplied to the rams depends at least in part on the vacuum and therewith of driving torque exerted upon the transmission by the engine of the motor vehicle.

24. A control system as claimed in claim 14 further comprising an accelerator pedal controlling the engine of the motor vehicle and means operable by said accelerator pedal to act on said pressure controller to increase the pressure in said conduits for arbitrarily actuating said valves.

25. A control system as claimed in claim 14 comprising a plurality of fluid-operable rams, each ram being operative upon individual actuation thereof to set the transmission to a correlated transmission ratio, the ram of the highest ratio being controlled by one of said pilot valves, gear shift valves individually connected to and operative to control the rams of the ratios other than the highest ratio and controlled by the other ones of said pilot valves, and fluid lines controlled by said one of said pilot valves and by said gear shift valves connecting said rams to said pressure controller, whereby the pressure supplied to the rams depends at least in part on the vacuum and therewith of driving torque exerted upon said transmission by the engine of the motor vehicle, a chamber associated with one of said gear shift valves, and at least one of said fluid lines communicating with said chamber, said last mentioned one of said gear shift valves controlling another one of said fluid lines and being operative to relieve said another one of said fluid lines when fluid under pressure is admitted to said chamber.

26. A control system for a motor vehicle transmission with a hydrodynamic clutch as claimed in claim 14,

furthe mp isiug a plura ylof fluid-opera le annrs slt ram being operative upon individual actuation thereof to set the transmission to a correlated transmission ratio, the ram of the highest ratio being controlled by one of said pilot valves, gear shift valves individually connected to and operative to control the rams of the ratios other. than the highest ratio and controlled by the other ones of said pilot valves, fluid lines controlled by said one of said pilot valves and by said gear shift valves connecting said rams to said pressure controller, whereby the pressure supplied to the rams depends on the vacuum and therewith of driving torque exerted upon said transmission by the engine of the motor vehicle, and an ad--- ditional fluid line connected to said pressure controller adapted to supply fluid to lubricating points and to said hydrodynamic clutch and to be opened by said pressure controller after all of said first mentioned lines have been opened by said pressure controller.

27. A control system as claimed in claim 10, further comprising a lever shiftable by the driver of the vehicle and operatively connected with said settable means, said lever being movablewithin either one of two parallel paths connected by a transverse path, and a spring-con;- trolled detent for resiliently blocking said transverse path.

28. In a multi-speed transmission comprising changespeed gear means having a shaft rotating at a speed proportional to the speed of the vehicle, means for controlling the shifting operation of said transmission by a fluid under pressure, pressure step controller means, means for drivingly connecting said pressure step controller means to said change speed gear means, said pressure step controller means being operative to control the pressure of said fluid in successive steps dependent on the speed of rotation of said shaft, and means operatively connected with said pressure step controller means for selectively varying the control elfect of said pressure step controller means to thereby vary the step-like successive changes of the pressure in said fluid.

29. The combination as defined in claim 28, wherein said last-mentioned means includes means for selectively disabling engagement of at least one of the transmission ratios of said change-speed gear by said means for controlling the shifting operation of said transmission.

30. In a multi-speed transmission comprising changespeed gear means having a shaft rotating at a speed proportional to the speed of the vehicle, pump means, pressure step controller means, means for drivingly connecting said pressure step controller means to said change speed gear means, said pressure step controller means being operative to control the pressure of said pump means in successive steps dependent on the speed of rotation of said shaft, and means for selectively varying the speed at which said pressure step controller means changes the pressure of said pump means in a step-like manner.

31. In a multi-speed transmission comprising changespeed gear means having a shaft rotating at a speed proportional to the speed of the vehicle, pump means for supplying a fluid under pressure, pressure step controller means, eans operatively connected to said pump means for controlling the shifting operation of said transmission by said fluid, means for driving connecting said pressure step controller-means to said change-speed gear means, said pressure step controller means being operative to control the pressure of said pump means in successive steps dependent on the speed of rotation of said shaft, and means operatively connected to said pressure step controller means for selectively varying the speed at which said pressure step controller means changes the pressure of said pump means in a step-like manner.

32. In a multi-speed transmission the combination according to claim 31 further comprising an engine connected with the input of said transmission for applying thereto torque, and means operative by the intake manifold vacuum and proportional at least in part in response to the torque thus produced'by said engine for controlling a 27 the means for controlling the shifting operation of said transmission.

33. In a multi-speed transmission the combination according to claim 32 further comprising means for actuating said means for controlling the shifting operation of said transmission independently of the pressure of said fluid.

34. A control system for a multi-speed motor vehicle transmission having a plurality of step-like selectively engageable transmission ratios comprising a hydraulic shifting system operated by a hydraulic shifting medium and having a fluid-actuated shifting mechanism for controlling the shifting operation of the transmission ratios of said transmission in dependence on the pressure of said hydraulic shifting medium, means connected in said hydraulic shifting'system for increasing the pressure of said hydraulic shifting medium in a step-like manner, and speed-responsive control means operated in dependence on the speed of the vehicle including a plurality of control elements successively operated one after another in dependence on said speed and a plurality of lines controlled by said control elements and connected with said firstmentioned means to thereby control said first-mentioned means over said lines by said successively operated control elements so as to increase the pressure of said hydraulic shifting medium in a step-like manner.

35. A control system according to claim 34, wherein said speed-responsive control means is formed as a centrifugal governor With said plurality of control elements thereof subjected to centrifugal forces and operative to close a corresponding number of said lines in a step-like manner to thereby control said first-mentioned means to mass-s open up the next line of the .successively controlled lines as a result of an increase in pressure in said hydraulic shifting medium. f 36. A control system according to claim 35 further comprising further control means operatively connected between said first-mentioned means and said speed responsive control means to open up only predetermined ones of said lines between said first-mentioned means and said speed-responsive control means so as to adjust thereby certain shifting ranges.

37. A control system according to claim 36, wherein said further control means is operative to alternately connect one and the same line section controlled by said firstmentionedmeans with different line sections controlled by said speed-responsive control means, and vice versa to connect one and the same line section controlled by said speed-responsive control means alternately with different line sections controlled by said first-mentioned means.

References Cited in the file of this patent UNITED STATES PATENTS 2,599,2l5 We mp June 3, 1952 2,609,706 Iandasek Sept. 9, 1952 2,627,189 McFarland Feb. 3, 1953 2,630,895 McFarland Mar. 10, 1953 2,640,373 Jandasek June 2, 1953 2,644,559 Randol July 7, 1953 FOREIGN PATENTS 503,755 Belgium June 30, 1951 

